Fisher CA-271 - Power Amplifier Adjustment; Integrated Circuit Block Diagram

POWER AMPLIFIER ADJUSTMENT
BEFORE ADJUSTMENT
Unplug the AC power cord and set the front panel controls as follows:
Power switch to the OFF position.
Set the SPEAKERS switch to the OFF position.
Turn the MASTER VOLUME control to the position marked 0 (minimum).
IDLING CURRENT ADJUSTMENT VR101/VR201 (on the Main P.C.Board) setting to mechanical
center position.
Connect the AC power cord and Power switch to the ON position.
IDLING CURRENT ADJUSTMENT
This adjustment is very sensitive to changes in ambient temperature. Allow set to operate for 5 mi-
nutes before attempting this adjustment.
*. EFT AMPLIFIER RIGHT AMPLIFIER
Connect the DC VTVM between Pins No.21 and 1) Connect the DC VTVM between Pins No.23 and
No.22 on the Main P.C.Board. No.24 on the Main P.C.Board.
Adjust the VR101 for an indication of 7mV on the 2) Adjust the VR201 for an indication of 7mV on the
DC VTVM. DC VTVM.
INTEGRATED CIRCUIT BLOCK DIAGRAM
FUNCTION ANALOG SWITCH IC LC 7815H
COM2 A2_ 82 C2 D2 TMout TMCTL Aout Bout Cout DouT MUTE
MUTING
CONTROL
TIMER
CIRCUIT
fe pe
RR AAR
; O O O O
COM1 Ai 81 C1 D1 TMIN AIN BIN. CIN DIN RESET MUTEIN CR
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